Chiral anomaly and longitudinal magnetotransport in type-II Weyl semimetals

In the presence of parallel electric and magnetic fields, the violation of a separate number conservation laws for the three-dimensional left-and right-handedWeyl fermions is known as the chiral anomaly. The recent discovery of Weyl and Dirac semimetals has paved the way for experimentally testing the effects of chiral anomaly via magnetotransportmeasurements, since chiral anomaly can lead to negative longitudinalmagnetoresistance (LMR) while the transverse magnetoresistance remains positive. More recently, a type-IIWeyl semimetal (WSM) phase has been proposed, where the nodal points possess a finite density of states due to the touching between electron and hole pockets. It has been suggested that the main difference between the two types of WSMs (type I and type II) is that in the latter, chiral-anomaly-induced negative LMR (positive longitudinal magnetoconductance) is strongly anisotropic, vanishing when the applied magnetic field is perpendicular to the direction of tilt ofWeyl fermion cones in a type-II WSM. We analyze chiral anomaly in a type-II WSM in a quasiclassical Boltzmann framework, and find that the chiral-anomaly-induced positive longitudinal magnetoconductivity is present along any arbitrary direction. Thus, our results are pertinent for uncovering transport signatures of type-II WSMs in different candidate materials.